Thermophone



p. GRAY. THERMOPHONE.

APPLICATION FILED FEB, 19, I920.

Patented Nov. 29, 1921.

W/EMTU UNITED STATES- A ENTQoFri c.

1 BUDD D. GRAY, OF GREENWICH, CONNECTICUT, ASSIG-NOR TO AMERICAN THERMO- PHONE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION" OF MASSACHU- SETTS.

To all whom it may concern:

Be it known that I,VBUDD Greenwich, in the county of Fairfield and State of Connecticut, a citizen of the United States, have invented a new and useful Improvement in-Thermophones, of which the following is a specification.

Because chiefly of its-smallsize and the minuteness of its thermic elements thedesigning and manufacture of a thermophone which will-give satisfactory results in practical use andwill beeasy and economical to make and easy to repair, have not been simple. 1

My invention relates to a thermophone construction designed especially for use as a receiver, which gives an opportunity for a large number of thermicv elements ar ranged in close proximity to each other-in a small symmetrical chamber so as to secure sensitiveness and strength without increasing the size ofthe instrument. By my construction a larger number of hot wires may be used than is customary and they are arranged about a chamber of a character particularly well shaped for the originating and ex elling of vocal sounds.

y invention will be understood by means of the, drawings in which it is shown in its preferred form.

Figure 1 is a longitudinal section of a thermophone embodying my invention,

Fig. 2 being a cross section on line 22of Fig. 1. v V

Fig. 3 is a side elevation.

Fig. 4 is a section of one .of the segments 7 from which the thermophone is made up.

Fig. 5 is a similar section showing the elements which it carrles in elevation.

Fig. 6 is a side elevation of one of the elements, and

Fig. 7 a section on line 7-7 of Fig. 6.

The thermophone as shown in Figs. 1, 2 and 3 is drawn on an enlarged scale, and the device as shown in Figs. 4, 5, 6"and 7 are still further enlarged.

As shown, the thermophone comprises a casing made up of four segments, each lettered A. It will be understood, however, that the thermophone may be composed of any convenient number of parts, the parts being made to form a casing or inclosure of suitable shape. 7 Each segment A is made of insulating material and is provided with openings through it as at a together with l). GRAY, of

'rnnmvrornonn 7 recesses 19 to receivefthe strips B which carry the thermic loops. Each segment also hasone or more. peripheral slots 6& to receive the wires by which the strips B may be connected in circuit. C, C are caps suitably shaped to fit over and hold the segments A together in their appropriate form, thecap C having an opening 0 through which the compressional air or heat waves escape to the ear in the ordinary use of the device.

In application for U. S. Letters Patent Serial No. 349,106, filed, January 2, 1920', there isshown amachine for making thermic elements of a. kind which may be used in this Specification of Letters Patent.- yatentetl NGV'QQQ, 1921. Application filed February 19, 1920. SerialNo. 259,948. Y

loops D of Wollaston wire. Asshown in Fig. 5, it will be noted that a small portion of the coating of-the wire has been etched off as at d, these portions being the hot portion of theelement. Thestrips B are, as

shown, set into the recesses?) which run the length of each'segment, and thereafter the segmentis used as 'aholder to hold theelements while they are being dipped for etching and also in the thermophone.

In making up the thermophone the segments carrying the strips B and loops D,

whatever their number, are brought together, for. example, asshown in Fig. 2, so that they abut against each otherv and bring the loops of the elements in close proximity, thoughvwithout touching; The.

cap C is placed over one end of the struc ture thus made and the cap C is placed over the other end. It will be noticed from Fig.

1 that wires a extend from the strips'B to the caps C, (l through' suitable openings in the segments. See Fig. '5 where the wires a pass down through the openings a and then through the grooves a to their objective,

As'I do not mean to limit myself toany particular connection of the elements with. the circuit, I do not mean to specify exactly how these wires run, because anyone skilled in the art will see that the elements carried by the four segments may be connected in a variety of ways, for example, either in series, or parallel, or series parallel. So this par 1 ticular type of apparatus lends itself to various ways of using a current. 1 i

As I have said above, I prefer for simplicity and compactness of construction to use four insulating segments which fit together to form a cylinder, but a greater or" less number of segments properly fitted together or otherwise to form either a cylinder of a polygon or any other convenient shape, may be used, my invention inthis regard lyingnot in the precise construction shown, but in the bringing and binding together of a number of segments of any convenient shape, each of which shall carry a plurality of thermic elements and which when combined will bring these elements into very close relation with each other in a chamber of any shape suitable for the purpose for which the instrument is designed. The thermophone may be of any desired length, thus enabling the number of thermicelements to be varied according to the circumstances of use and, because or the comparatively large number of loops which may be located in the small air space when arranged as above described, the etched portion of each Wollaston wire be much shorter than heretofore and the loops as a whole much stronger so that the device may receive quite hard usage without fracture. plication above referred to units of considerable length may be easily connected and cut into lengths corresponding to the length of the thermophone in which'they are to be used. The purpose of the caps is to clamp the segments together so that they will form an air chamber within which the desired thermic results, may be secured and from As described in the ap-,

more or said thermic units arranged parallel to each other and projecting therefrom into said chamber in a plane or planes crosswise or the length thereof, and means for connecting said units with a source of current.

52. The device above described comprising a cha ibered casing made of insulating material and heat units located in the cham her in said casing and supported by said casing and arranged radially in planes at right angles to the aXis of said chamber.

3. The device above described comprising gments, said segments being arranged to form chambered casing, and means comrisin caps to hold said segments together, and close ends of the air space, one of said caps being perforated to form an outlet to said chamber in combination with Wollaston' said chamber and in planes at substantiallyright angles to the said axis,

5. Ina device of thelzind described,"a series of segments of insulating material, each segmentcarrying parallel strips of conducting material, VVollaston wires connecting said strips, and means for holding'said segments together to inclose a chamber, said Wollaston wires lying in planes at right angles to the length of said chamber.

' BUDD D; GRAY. 

